Video signal superimposing device

Abstract

A video signal superimposing device for superimposing and clearly displaying video signals produced from at least two discrete systems includes an input terminal for inputting a color complex video signal, a separation circuit for separating a first brightness signal and a first chroma signal from the color complex video signal, a first generator for generating a second brightness signal, a first mixer circuit for mixing the second brightness signal and the first brightness signal separated by the separation circuit, a second generator for generating a second chroma signal, a second mixer circuit for mixing the second chroma signal and the first chroma signal separated by the separation circuit, and a third mixer circuit for mixing the mixed brightness signal applied from the first mixer circuit and the mixed chroma signal applied to the second mixer circuit.

What is claimed is: 
     
       1. A video signal superimposing device for superimposing and displaying video signals produced from at least two systems comprising: first input means for inputting a color complex video signal;   means for producing a burst signal from said color complex video signal;   separation means for separating a first brightness signal and a first chroma signal from the color complex video signal;   second input means for inputting R.G.B. signals;   first generation means for generating a second brightness signal from said R.G.B. signals;   first mixer means for mixing the second brightness signal and the first brightness signal separated by the separation means to form a mixed brightness signal;   second generation means responsive to said burst signal for generating a second chroma signal from said R.G.B. signals;   second mixer means for mixing the second chroma signal and the first chroma signal separated by the separation means to form a mixed chroma signal; and   third mixer means for mixing the mixed brightness signal applied from the first mixer means and the mixed chroma signal applied to the second mixer means to form a combined signal.   
     
     
       2. The video signal superimposing device of claim 1, wherein the two systems are a video imaging system and a personal computer system. 
     
     
       3. The video signal superimposing device of claim 2, wherein the video imaging system is a television, a video recorder, or a video disc. 
     
     
       4. The video signal superimposing device of claim 1, wherein the superimposing device is built into a personal computer. 
     
     
       5. The video signal superimposing device of claim 1, wherein the video signal superimposing device is built into a video imaging system. 
     
     
       6. A video signal superimposing device for superimposing and displaying video signals from at least two systems comprising: input means for inputting a color complex video signal;   separation means for separating a first brightness signal component and a first chroma signal component from the color complex video signal;   second input means for inputting first R.G.B. signals;   first generation means for generating a second brightness signal from said first R.G.B. signals;   first mixer means for mixing the second brightness signal and the first brightness signal separated by the separation means to form a mixed brightness signal;   demodulation means for demodulating the first chroma signal separated by the separation means so as to form second R.G.B. signals;   second mixer means for mixing the first R.G.B. signals and the second R.G.B. signals produced from the demodulation means, respectively to form a mixed R.G.B. signal;   second generation means for generating a second chroma signal based on the mixed R.G.B. signal; and   third mixer means for mixing the mixed brightness signal and the second chroma signal to form a combined signal.   
     
     
       7. The video signal superimposing device of claim 6, further comprising: gate means for separating a burst signal component from the color complex video signal;   third generation means for generating a color subcarrier signal based on the burst signal, in which the demodulation means is operated to demodulate the first chroma signal based on the color subcarrier signal, and the second generation means is operated to generate the second chroma signal based on the color subcarrier signal.   
     
     
       8. A method for superimposing a second signal onto a first signal to produce a combined video signal comprising the steps of: inputting a color complex video signal as the first signal;   producing a burst signal from said color complex video signal;   separating said color complex video signal into a first chroma signal and a first brightness signal;   inputting R.G.B. signals as the second signal;   producing a second brightness signal from said R.G.B. signals;   producing a subcarrier signal from said burst signal;   producing a second chroma signal from said R.G.B. signals using said subcarrier signal;   combining said first and second chroma signals to form a mixed chroma signal;   combining said first and second brightness signals to form a mixed brightness signal; and   combining said mixed chroma signal and said mixed brightness signal to form the combined video signal.   
     
     
       9. A method for superimposing a second signal onto a first signal to produce a combined video signal comprising the steps of: inputting a color complex video signal as the first signal;   separating said color complex video signal into a first chroma signal and a first brightness signal;   inputting first R.G.B. signals as the second signal;   producing a second brightness signal from said first R.G.B. signals;   combining said first and second brightness signals to form a mixed brightness signal;   demodulating said first chroma signal to produce second R.G.B. signals;   combining said first and second R.G.B. signals to produce a mixed R.G.B. signal;   producing a burst signal from said color complex video signal;   producing a subcarrier signal from said burst signal;   producing a mixed chroma signal from said mixed R.G.B. signal using said subcarrier signal;   combining said chroma signal and said mixed brightness signal to form the combined video signal.